Why does this test trigger a Robolectric Delegate runner RuntimeException?

Question

I'm writing an integration test for a UI component.

The test is outlined as such:

package filter.clear

import android.view.View
import android.widget.SearchView
import androidx.test.core.app.ApplicationProvider
import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.filters.SmallTest
import com.foo. /* ... several business-logic imports */
import org.junit.runner.RunWith
import org.robolectric.annotation.Config
import kotlin.test.assertEquals

@SmallTest
@RunWith(AndroidJUnit4::class)
@Config(manifest=Config.NONE)
class TestClearSearchView {

    private fun searchView() = SearchView(ApplicationProvider.getApplicationContext())

    fun clearShouldClearSearchViewQuery() {

        // Given
        val searchView = searchView()
        val clearFilterView = ClearFilterView()
        // ...

        // When
        clearFilterView.view.callOnClick()

        // Expect
        assertEquals(searchView.query, "")
    }
}

However, running the test class (or directly the test method) results in Robolectric throwing a RuntimeException:

java.lang.RuntimeException: Delegate runner 'org.robolectric.RobolectricTestRunner' for AndroidJUnit4 could not be loaded.

    at androidx.test.ext.junit.runners.AndroidJUnit4.throwInitializationError(AndroidJUnit4.java:92)
    at androidx.test.ext.junit.runners.AndroidJUnit4.loadRunner(AndroidJUnit4.java:82)
    at androidx.test.ext.junit.runners.AndroidJUnit4.loadRunner(AndroidJUnit4.java:51)
    at androidx.test.ext.junit.runners.AndroidJUnit4.<init>(AndroidJUnit4.java:46)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:101)
    at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:87)
    at com.intellij.junit4.JUnit46ClassesRequestBuilder.collectWrappedRunners(JUnit46ClassesRequestBuilder.java:86)
    at com.intellij.junit4.JUnit46ClassesRequestBuilder.getClassesRequest(JUnit46ClassesRequestBuilder.java:47)
    at com.intellij.junit4.JUnit4TestRunnerUtil.buildRequest(JUnit4TestRunnerUtil.java:90)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:46)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at androidx.test.ext.junit.runners.AndroidJUnit4.loadRunner(AndroidJUnit4.java:72)
    ... 20 more
Caused by: org.junit.runners.model.InitializationError
    at org.junit.runners.ParentRunner.validate(ParentRunner.java:418)
    at org.junit.runners.ParentRunner.<init>(ParentRunner.java:84)
    at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
    at org.robolectric.internal.SandboxTestRunner.<init>(SandboxTestRunner.java:56)
    at org.robolectric.RobolectricTestRunner.<init>(RobolectricTestRunner.java:92)
    ... 25 more

Answer 1

You forgot to mark the method as @Test.

@@ -11,7 +11,6 @@
 import com.foo. /* ... several business-logic imports */
+import org.junit.Test
 import org.junit.runner.RunWith
 import org.robolectric.annotation.Config
 import kotlin.test.assertEquals
@@ -34,7 +33,6 @@

+    @Test
     fun clearShouldClearSearchViewQuery() {